Cellular Respiration Flashcards
What is photosynthesis
This is only for plants, it is light energy to chemical energy, During photosynthesis in green plants, light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds
What is the photosynthesis equation
6CO2 + 6H2O → C6H12O6 + 6O2.
Low energy to high energy, the CO2 is low energy while the O2 is high energy
What is the definition of cellular respiration
Where cells derive energy from glucose. The chemical reaction that is happening involves glucose and oxygen as inputs and produces carbon dioxide, water and energy as outputs (energy is in the form of ATP). This is all happening in the mitochondria and it doesn’t only happen in animals but also plants , so happens in plants and animals
The chemical formula is. C6H12O6 + 6O2 –> 6CO2 + 6H2O + ATP
What is ATP
The name - adenosine tri phosphate
ATP is a energy carrier allowing us to enable energy as having too much energy is bad
Why do we need energy give 4 reasons
1) for mechanical work - to move things around, an example is moving protons, it requires ATP to move across the cytoskeleton, how this works is that we take a phosphate group from the ATP making ADP + P1 and this drives the movement
2) making new materials - for example, for growth and replacement, making new cells
3) for transport- transport of molecules across membrane, this could be like moving against the concentration gradient as we need to push the molecules across
4) to maintain order - maintaining everything the way it is requires energy, so keeping the way things are needs energy.
What is the mitochondria
This is the site of cellular respiration, this is the conversion of chemical energy C 6 H 12 O 6 ( this is a hexacciride as it has 6 carbon sugars packed with energy) + 6 O 2 –> 6 CO 2 ( low energy molecule) + 6 H 2 O + ATP
What is the mitochondria structure
It is an organelle. The mitrocondria use to be its own bacteria and then it was enfolded by another cell and then it became an organelle and now we can break down glucose and get lots of ATP
- the mitochondria Varys in length so some can be longer than others like 1-10 micrometers long
- they can very in number in each cell, so depending on the cell type and energy requirements of the cell type you can have 1-1000s per mitochondria. An example can be the muscle cell which requires a lot of energy and so is going to have a lot of mitrocondra to supply ATP
- the mitrocondra also contains mitrocondral DNA and ribosomes , and a fun fact, this was the first hint that people knew and saw that they were independent organisms. They are able to make some of the proteins but not all, so now they rely on host to supply some proteins for them.
- the mitochondria has 2 membranes, the inner and outer membrane and both of them are lipid bylairs , this is similar to the plasma membrane and there are also protons that are floating in it.
- in the middle of the membrane/ in the centre there is a mitrocondrial matrix, there are many things in here like water, enzymes, lots of molecules, proteins, ATP, Ribosomes, DNA.
- THE INNER membrane is highly folded and we call these CRISTAE these are functionally important as they house massive protein complexes that are included in respiration
- the mitochondria also has inner membrane space, this is functionally important as well as this is how they generate ATP
What is cristae
This is the inner membrane that has the massive protein complexes
How does cellular respiration work, what is the first stage
Harvesting chemical energy form glucose occurs in 3 stages. So the first stage of cellular respiration is happening at the CYTOSOL - this is where the process starts, with the glucose molecule ( 6 C molecules ) and an enzyme splits a molecule of glucose into 2 molecules of pyruvate (2 times 3 C molecules) and as we split the glucose we realise some energy that makes ATP. So in this stage we generate 2ATP and we also get some electrons as we are making the pyruvate and we also get NADH formed
What is the second stage of cellular respiration
The second stage happens in the mitochondrial matrix
So now the pyruvate has a lot of energy that the glucose had thus makes the pyruvate a high energy molecule, and what we do in this stage is that we move the pyruvate from the cytosol, across the outer membrane, across the inner membrane and into the mitrocondra matrix.
So 2 things happen in the mitochondria matrix, first the pyruvate gets converted into 2 Acetyl CoA, ( 2 Acetyl is 2 carbon molecules that generate high energy electrons) and the CoA makes more NADH and then it enters the citric acid cycle and the Acetyl CoA gets completely broken down in there citric acid is used to make a collection of high-energy intermediates that will ultimately make adenosine triphosphate (ATP). and so as a result we get 2ATP and also high energy electrons carriers NADH and FADH2, so FADH2 has slighty different energry from the other electrons, so the electrons that don’t have enough energy to go to NADH go to FADH2
What is the third stage of cellular respiration
This happens in the inner membrane of the mitrocondra. So in the stage we are trying to find a way to convert high energy electrons (NADH) into ATP and this process is called OXIDATE PHOSPHORYLATION.
ok so how we do this is that we take the high energy electrons from NDAH AND FDAH2 and we put them down in an electron transport chain ( these are embedded in the inner membrane) and also in here will be proton complexes, ( proton complexes 1,2,3,4 ) and the electrons go through here, but with FDAH2 it doesn’t go to the proton complex 1 it goes to 2 while NADH starts at 1. As the elections are going through the protein complexes this allows the energy from the elections to be used to pump proteins across the membrane, forming a gradient with protons accumulating in the inner membrane space much more than the mitrocondral matrix and because we want the protons to be in the maxtrix we use something called “ATP synthase” Protons flow back into the matrix through an enzyme called ATP synthase, making ATP( a lot of ATP), NOTE- this is from high concentration to low concentration gradient.
and also as the electrons are making the proteins through the protein complexes their energy will be less and less From here the energy is no longer in the electron it’s now in the concentration of protons (H+) and we use the concentration of the protons to produce ATP.
What happens to the electrons at the end of stage 3
At the end of the electron transport chain, oxygen accepts electrons and takes up protons to form water.
What is ATP synthase
This is how Protons flow back into the matrix from the inner membrane through an enzyme called ATP synthase, making ATP.
What’s so special about ATP
- enables controlled release of energy
- provides the energy needed for many essential processes in organisms and cells
